-
Double Chooz Collaboration,
Y. Abe,
C. Aberle,
J. C. dos Anjos,
J. C. Barriere,
M. Bergevin,
A. Bernstein,
T. J. C. Bezerra,
L. Bezrukhov,
E. Blucher, [......],
C. Veyssiere,
S. Wagner,
H. Watanabe,
B. White,
C. Wiebusch,
L. Winslow,
M. Worcester,
M. Wurm,
F. Yermia,
V. Zimmer
[show abstract]
[hide abstract]
ABSTRACT: The Double Chooz experiment has determined the value of the neutrino
oscillation parameter $\theta_{13}$ from an analysis of inverse beta decay
interactions with neutron capture on hydrogen. This analysis uses a three times
larger fiducial volume than the standard Double Chooz assessment, which is
restricted to a region doped with gadolinium (Gd), yielding an exposure of
113.1 GW-ton-years. The data sample used in this analysis is distinct from that
of the Gd analysis, and the systematic uncertainties are also largely
independent, with some exceptions, such as the reactor neutrino flux
prediction. A combined rate- and energy-dependent fit finds $\sin^2
2\theta_{13}=0.097\pm 0.034(stat.) \pm 0.034 (syst.)$, excluding the
no-oscillation hypothesis at 2.0 \sigma. This result is consistent with
previous measurements of $\sin^2 2\theta_{13}$.
01/2013;
-
Y. Abe,
C. Aberle,
J. C. dos Anjos,
J. C. Barriere,
M. Bergevin,
A. Bernstein,
T. J. C. Bezerra,
L. Bezrukhov,
E. Blucher,
N. S. Bowden, [......],
C. Veyssiere,
S. Wagner,
H. Watanabe,
B. White,
C. Wiebusch,
L. Winslow,
M. Worcester,
M. Wurm,
F. Yermia,
V. Zimmer
[show abstract]
[hide abstract]
ABSTRACT: Double Chooz is unique among modern reactor-based neutrino experiments studying ν̅ e disappearance in that data can be collected with all reactors off. In this paper, we present data from 7.53 days of reactor-off running. Applying the same selection criteria as used in the Double Chooz reactor-on oscillation analysis, a measured background rate of 1.0±0.4 events/day is obtained. The background model for accidentals, cosmogenic β-n-emitting isotopes, fast neutrons from cosmic muons, and stopped-μ decays used in the oscillation analysis is demonstrated to be correct within the uncertainties. Kinematic distributions of the events, which are dominantly cosmic-ray-produced correlated-background events, are provided. The background rates are scaled to the shielding depths of two other reactor-based oscillation experiments, Daya Bay and RENO.
Physical Review D 01/2013; 87(1):011102. · 4.56 Impact Factor
-
Y. Abe,
C. Aberle,
J. C. dos Anjos,
J. C. Barriere,
M. Bergevin,
A. Bernstein,
T. J. C. Bezerra,
L. Bezrukhov,
E. Blucher,
N. S. Bowden, [......],
S. Wagner,
H. Watanabe,
B. White,
C. Wiebusch,
L. Winslow,
M. Worcester,
M. Wurm,
F. Yermia,
V. Zimmer,
G. Valdiviesso
[show abstract]
[hide abstract]
ABSTRACT: We present a search for Lorentz violation with 8249 candidate electron antineutrino events taken by the Double Chooz experiment in 227.9 live days of running. This analysis, featuring a search for a sidereal time dependence of the events, is the first test of Lorentz invariance using a reactor-based antineutrino source. No sidereal variation is present in the data and the disappearance results are consistent with sidereal time independent oscillations. Under the Standard-Model Extension, we set the first limits on 14 Lorentz violating coefficients associated with transitions between electron and tau flavor, and set two competitive limits associated with transitions between electron and muon flavor.
Physical Review D 12/2012; 86:112009. · 4.56 Impact Factor
-
4th International Euro-Mediterranean Conference (EuroMed 2012), Limassol, Cyprus; 10/2012
-
Y. Abe,
C. Aberle,
J. C. dos Anjos,
J. C. Barriere,
M. Bergevin,
A. Bernstein,
T. J. C. Bezerra,
L. Bezrukhov,
E. Blucher,
N. S. Bowden, [......],
C. Veyssiere,
S. Wagner,
H. Watanabe,
B. White,
C. Wiebusch,
L. Winslow,
M. Worcester,
M. Wurm,
F. Yermia,
V. Zimmer
[show abstract]
[hide abstract]
ABSTRACT: Double Chooz is unique among modern reactor-based neutrino experiments
studying $\bar \nu_e$ disappearance in that data can be collected with all
reactors off. In this paper, we present data from 7.53 days of reactor-off
running. Applying the same selection criteria as used in the Double Chooz
reactor-on oscillation analysis, a measured background rate of 1.0$\pm$0.4
events/day is obtained. The background model for accidentals, cosmogenic
$\beta$-$n$-emitting isotopes, fast neutrons from cosmic muons, and
stopped-$\mu$ decays used in the oscillation analysis is demonstrated to be
correct within the uncertainties. Kinematic distributions of the events, which
are dominantly cosmic-ray-produced correlated-background events, are provided.
The background rates are scaled to the shielding depths of two other
reactor-based oscillation experiments, Daya Bay and RENO.
10/2012;
-
Double Chooz Collaboration,
Y. Abe,
C. Aberle,
J. C. dos Anjos,
M. Bergevin,
A. Bernstein,
T. J. C. Bezerra,
L. Bezrukhov,
E. Blucher,
N. S. Bowden, [......],
S. Wagner,
H. Watanabe,
B. White,
C. Wiebusch,
L. Winslow,
M. Worcester,
M. Wurm,
E. Yanovitch,
F. Yermia,
V. Zimmer
[show abstract]
[hide abstract]
ABSTRACT: We present a search for Lorentz violation with 8249 candidate electron
antineutrino events taken by the Double Chooz experiment in 227.9 live days of
running. This analysis, featuring a search for a sidereal time dependence of
the events, is the first test of Lorentz invariance using a reactor-based
antineutrino source. No sidereal variation is present in the data and the
disappearance results are consistent with sidereal time independent
oscillations. Under the Standard-Model Extension (SME), we set the first limits
on fourteen Lorentz violating coefficients associated with transitions between
electron and tau flavor, and set two competitive limits associated with
transitions between electron and muon flavor.
09/2012;
-
Y Abe,
C Aberle,
J C Anjos,
J C Barriere,
M Bergevin,
A Bernstein,
T J C Bezerra,
L Bezrukhov,
E Blucher,
N S Bowden, [......],
C Veyssiere,
S Wagner,
H Watanabe,
B White,
C Wiebusch,
L Winslow,
M Worcester,
M Wurm,
F Yermia,
V Zimmer
Phys. Rev. D. 09/2012; 86(5):052008.
-
Y Abe,
C Aberle,
J C Anjos,
J C Barriere,
M Bergevin,
A Bernstein,
T J C Bezerra,
L Bezrukhov,
E Blucher,
N S Bowden, [......],
C Veyssiere,
S Wagner,
H Watanabe,
B White,
C Wiebusch,
L Winslow,
M Worcester,
M Wurm,
F Yermia,
V Zimmer
Phys. Rev. D. 09/2012; 86(5):052008.
-
Y. Abe,
C. Aberle,
J. C. dos Anjos,
J. C. Barriere,
M. Bergevin,
A. Bernstein,
T. J. C. Bezerra,
L. Bezrukhov,
E. Blucher,
N. S. Bowden, [......],
C. Veyssiere,
S. Wagner,
H. Watanabe,
B. White,
C. Wiebusch,
L. Winslow,
M. Worcester,
M. Wurm,
F. Yermia,
V. Zimmer
[show abstract]
[hide abstract]
ABSTRACT: The Double Chooz experiment has observed 8,249 candidate electron
antineutrino events in 227.93 live days with 33.71 GW-ton-years (reactor power
x detector mass x livetime) exposure using a 10.3 cubic meter fiducial volume
detector located at 1050 m from the reactor cores of the Chooz nuclear power
plant in France. The expectation in case of theta13 = 0 is 8,937 events. The
deficit is interpreted as evidence of electron antineutrino disappearance. From
a rate plus spectral shape analysis we find sin^2 2{\theta}13 = 0.109 \pm
0.030(stat) \pm 0.025(syst). The data exclude the no-oscillation hypothesis at
99.8% CL (2.9{\sigma}).
07/2012;
-
S. CMS Collaboration Chatrchyan,
V. Khachatryan,
A. M. Sirunyan,
A. Tumasyan,
W. Adam,
T. Bergauer,
M. Dragicevic,
J. Erö,
C. Fabjan,
M. Friedl, [......],
C. Lazaridis,
J. Leonard,
R. Loveless,
A. Mohapatra,
I. Ojalvo,
G. A. Pierro,
I. Ross,
A. Savin,
W. H. Smith,
J. Swanson
[show abstract]
[hide abstract]
ABSTRACT: A search for neutral Higgs bosons decaying to tau pairs at a
center-of-mass energy of 7 TeV is performed using a dataset
corresponding to an integrated luminosity of 4.6 fb-1
recorded by the CMS experiment at the LHC. The search is sensitive to
both the standard model Higgs boson and to the neutral Higgs bosons
predicted by the minimal supersymmetric extension of the standard model
(MSSM). No excess of events is observed in the tau-pair invariant-mass
spectrum. For a standard model Higgs boson in the mass range of
110-145 GeV upper limits at 95% confidence level (CL) on the
production cross section are determined. We exclude a Higgs boson with
mH=115 GeV with a production cross section 3.2 times of
that predicted by the standard model. In the MSSM, upper limits on the
neutral Higgs boson production cross section times branching fraction to
tau pairs, as a function of the pseudoscalar Higgs boson mass,
mA, sets stringent new bounds in the parameter space,
excluding at 95% CL values of tan β as low as 7.1 at
mA=160 GeV in the mhmax benchmark scenario.
Physics Letters B 05/2012; 713:68-90. · 3.95 Impact Factor
-
The CMS Collaboration,
S. Chatrchyan,
V. Khachatryan,
A. M. Sirunyan,
A. Tumasyan,
W. Adam,
T. Bergauer,
M. Dragicevic,
J. Erö,
C. Fabjan, [......],
J. Leonard,
R. Loveless,
A. Mohapatra,
F. Palmonari,
D. Reeder,
I. Ross,
A. Savin,
W. H. Smith,
J. Swanson,
M. Weinberg
[show abstract]
[hide abstract]
ABSTRACT: A measurement of the t[`(t)]\mathrm{t{\bar{t}}} production cross section in proton-proton collisions at a centre-of-mass energy of 7TeV has been performed at the LHC with
the CMS detector. The analysis uses a data sample corresponding to an integrated luminosity of 36pb−1 and is based on the reconstruction of the final state with one isolated, high transverse-momentum electron or muon and three
or more hadronic jets. The kinematic properties of the events are used to separate the t[`(t)]\mathrm{t{\bar{t}}} signal from W+jets and QCD multijet background events. The measured cross section is 173+39-32(stat. + syst.)173^{+39}_{-32}~(\mathrm{stat}. + \mathrm{syst}.)pb, consistent with standard model expectations.
European Physical Journal C 05/2012; 71(9):1-27. · 3.63 Impact Factor
-
The CMS Collaboration,
S. Chatrchyan,
V. Khachatryan,
A. M. Sirunyan,
A. Tumasyan,
W. Adam,
T. Bergauer,
M. Dragicevic,
J. Erö,
C. Fabjan, [......],
J. Leonard,
R. Loveless,
A. Mohapatra,
F. Palmonari,
D. Reeder,
I. Ross,
A. Savin,
W. H. Smith,
J. Swanson,
M. Weinberg
[show abstract]
[hide abstract]
ABSTRACT: A search for new physics is presented based on an event signature of at least three jets accompanied by large missing transverse
momentum, using a data sample corresponding to an integrated luminosity of 36 pb−1 collected in proton-proton collisions at Ös = 7 \sqrt {s} = 7 TeV with the CMS detector at the LHC. No excess of events is observed above the expected standard model backgrounds, which
are all estimated from the data. Exclusion limits are presented for the constrained minimal supersymmetric extension of the
standard model. Cross section limits are also presented using simplified models with new particles decaying to an undetected
particle and one or two jets.
KeywordsHadron-Hadron Scattering
Journal of High Energy Physics 04/2012; 2011(8):1-46. · 5.83 Impact Factor
-
The CMS collaboration,
S. Chatrchyan,
V. Khachatryan,
A. M. Sirunyan,
A. Tumasyan,
W. Adam,
T. Bergauer,
M. Dragicevic,
J. Erö,
C. Fabjan, [......],
J. Leonard,
R. Loveless,
A. Mohapatra,
F. Palmonari,
D. Reeder,
I. Ross,
A. Savin,
W. H. Smith,
J. Swanson,
M. Weinberg
[show abstract]
[hide abstract]
ABSTRACT: The first measurement of inclusive Z → τ
+
τ
− production in pp collisions at the LHC is presented, in the final states μ + hadrons, e + hadrons, e + μ, and μ + μ. The data sample corresponds to an integrated luminosity of 36 pb−1 collected with the CMS detector. The measured cross section is σ (pp → ZX) × B (Z → τ
+
τ
−) = 1.00 ± 0.05(stat.) ± 0.08(syst.) ± 0.04(lumi.)nb, which is in good agreement with the next-to-next-to-leading order QCD prediction and improves on previous measurements
in the Z → e+e− and μ
+
μ
− channels. The reconstruction efficiency for hadronic τ decays is determined with a precision of 7%.
KeywordsHadron-Hadron Scattering
Journal of High Energy Physics 04/2012; 2011(8):1-32. · 5.83 Impact Factor
-
The CMS Collaboration,
S. Chatrchyan,
V. Khachatryan,
A. M. Sirunyan,
A. Tumasyan,
W. Adam,
T. Bergauer,
M. Dragicevic,
J. Erö,
C. Fabjan, [......],
J. Leonard,
R. Loveless,
A. Mohapatra,
F. Palmonari,
D. Reeder,
I. Ross,
A. Savin,
W. H. Smith,
J. Swanson,
M. Weinberg
[show abstract]
[hide abstract]
ABSTRACT: A measurement of the underlying activity in events with a jet of transverse momentum in the several GeV region is performed
in proton-proton collisions at Ös = 0.9 \sqrt {s} = 0.9 and 7 TeV, using data collected by the CMS experiment at the LHC. The production of charged particles with pseudorapidity
|η| < 2 and transverse momentum p
T
> 0.5GeV/c is studied in the azimuthal region transverse to that of the leading set of charged particles forming a track-jet. A significant
growth of the average multiplicity and scalar-p
T
sum of the particles in the transverse region is observed with increasing p
T
of the leading track-jet, followed by a much slower rise above a few GeV/c. For track-jet p
T
larger than a few GeV/c, the activity in the transverse region is approximately doubled with a centre-of-mass energy increase
from 0.9 to 7 TeV. Predictions of several QCD-inspired models as implemented in pythia are compared to the data.
KeywordsHadron-Hadron Scattering
Journal of High Energy Physics 04/2012; 2011(9):1-31. · 5.83 Impact Factor
-
The CMS collaboration,
S. Chatrchyan,
V. Khachatryan,
A. M. Sirunyan,
A. Tumasyan,
W. Adam,
T. Bergauer,
M. Dragicevic,
J. Erö,
C. Fabjan, [......],
J. Leonard,
R. Loveless,
A. Mohapatra,
F. Palmonari,
D. Reeder,
I. Ross,
A. Savin,
W. H. Smith,
J. Swanson,
M. Weinberg
[show abstract]
[hide abstract]
ABSTRACT: A search is performed for an excess of events, over the standard model expectations, with a photon, a lepton, and large missing
transverse energy in pp collisions at Ös = 7 \sqrt {s} = 7 TeV. Such events are expected in many new physics models, in particular a supersymmetric theory that is broken via a gauge-mediated
mechanism, when the lightest charged and neutral gauginos are mass degenerate. The data sample used in this search corresponds
to an integrated luminosity of 35 pb-1 collected with the CMS detector at the LHC. No evidence of such an excess above the standard model backgrounds, dominated
by W production, is found. The results are presented as 95% confidence level upper limits on the cross section for a benchmark
gauge-mediated scenario, and are then converted into exclusion limits on the squark, gluino, and wino masses.
KeywordsHadron-Hadron Scattering
Journal of High Energy Physics 04/2012; 2011(6):1-28. · 5.83 Impact Factor
-
The CMS collaboration,
S. Chatrchyan,
V. Khachatryan,
A. M. Sirunyan,
A. Tumasyan,
W. Adam,
T. Bergauer,
M. Dragicevic,
J. Erö,
C. Fabjan, [......],
J. Leonard,
R. Loveless,
A. Mohapatra,
F. Palmonari,
D. Reeder,
I. Ross,
A. Savin,
W. H. Smith,
J. Swanson,
M. Weinberg
[show abstract]
[hide abstract]
ABSTRACT: A search for narrow resonances at high mass in the dimuon and dielectron channels has been performed by the CMS experiment
at the CERN LHC, using pp collision data recorded at Ös = 7 \sqrt {s} = 7 TeV. The event samples correspond to integrated luminosities of 40 pb−1 in the dimuon channel and 35 pb−1 in the dielectron channel. Heavy dilepton resonances are predicted in theoretical models with extra gauge bosons (Z′) or
as Kaluza-Klein graviton excitations (GKK) in the Randall-Sundrum model. Upper limits on the inclusive cross section of Z′(GKK) → ℓ
+
ℓ
− relative to Z → ℓ
+
ℓ
− are presented. These limits exclude at 95% confidence level a Z′ with standard-model-like couplings below 1140GeV, the superstring-inspired
Z
ψ
′ below 887 GeV, and, for values of the coupling parameter
k /
[`(M)] \textPl {{k} \left/ {{{{\overline M }_{\text{Pl}}}}} \right.} of 0.05 (0.1), Kaluza-Klein gravitons below 855 (1079) GeV.
KeywordsHadron-Hadron Scattering
Journal of High Energy Physics 04/2012; 2011(5):1-35. · 5.83 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: A chickpea F2 population of 593 plants derived from the intraspecific cross ILC3279×WR315 was genotyped for markers closely linked to
quantitative trait loci (QTLs) for ascochyta blight resistance (QTLAR1 and QTLAR2 located on linkage group 4 and QTLAR3 on linkage group 2). All the markers located on linkage group 4 exhibited strongly distorted segregation with respect to
the expected Mendelian inheritance, towards the male parental line. This skewed segregation was also observed in a second
F2 population of 50 plants derived from the same cross, confirming the presence of a region of distorted segregation on this
linkage group and its heritability. The most skewed markers were SC-Y17 and TA72, which were tightly linked to each other,
indicating that they may both be closely associated with the genetic factor responsible for segregation distortion in chickpea.
To attempt to explain the non-Mendelian segregation, by identifying factors to which it could be attributed, three different
chi-square tests were carried out to test different hypotheses using the data obtained from examining co-dominant markers
associated with segregation distortion. According to our results, the distorted segregation could be caused by gametophytic
factors that affect either male or female gametes. Pollen fertility and meiosis were also analysed to determine their relationship
with segregation distortion; however, these not seem to be inducing factors in the non-Mendelian segregation reported in this
study.
KeywordsSegregation distortion–Molecular markers–Gametic selection–Chickpea
Euphytica 04/2012; 179(3):515-523. · 1.55 Impact Factor
-
The CMS Collaboration,
V. Khachatryan,
A. M. Sirunyan,
A. Tumasyan,
W. Adam,
T. Bergauer,
M. Dragicevic,
J. Erö,
C. Fabjan,
M. Friedl, [......],
D. Lomidze,
R. Loveless,
A. Mohapatra,
W. Parker,
D. Reeder,
I. Ross,
A. Savin,
W. H. Smith,
J. Swanson,
M. Weinberg
[show abstract]
[hide abstract]
ABSTRACT: The production of J/ψ mesons is studied in pp collisions at Ös = 7\sqrt{s} = 7TeV with the CMS experiment at the LHC. The measurement is based on a dimuon sample corresponding to an integrated luminosity
of 314nb−1. The J/ψ differential cross section is determined, as a function of the J/ψ transverse momentum, in three rapidity ranges. Afit to the decay length distribution is used to separate the prompt from
the non-prompt (b hadron toJ/ψ) component. Integrated over J/ψ transverse momentum from6.5 to 30GeV/c and over rapidity in the range |y|<2.4, the measured cross sections, times the dimuon decay branching fraction, are 70.9±2.1(stat.)±3.0(syst.)±7.8(luminosity)nb
for prompt J/ψ mesons assuming unpolarized production and 26.0±1.4(stat.)±1.6(syst.)±2.9(luminosity)nb for J/ψ mesons from b-hadron decays.
European Physical Journal C 04/2012; 71(3):1-26. · 3.63 Impact Factor
-
The CMS collaboration,
V. Khachatryan,
A. M. Sirunyan,
A. Tumasyan,
W. Adam,
T. Bergauer,
M. Dragicevic,
J. Erö,
C. Fabjan,
M. Friedl, [......],
C. Lazaridis,
J. Leonard,
R. Loveless,
A. Mohapatra,
D. Reeder,
I. Ross,
A. Savin,
W. H. Smith,
J. Swanson,
M. Weinberg
[show abstract]
[hide abstract]
ABSTRACT: Bose-Einstein correlations between identical particles are measured in samples of proton-proton collisions at 0.9 and 7 TeV
centre-of-mass energies, recorded by the CMS experiment at the LHC. The signal is observed in the form of an enhancement of
number of pairs of same-sign charged particles with small relative momentum. The dependence of this enhancement on kinematic
and topological features of the event is studied. Anticorrelations between same-sign charged particles are observed in the
region of relative momenta higher than those in the signal region.
KeywordHadron-Hadron Scattering
Journal of High Energy Physics 04/2012; 2011(5):1-29. · 5.83 Impact Factor
-
The CMS collaboration,
S. Chatrchyan,
V. Khachatryan,
A. M. Sirunyan,
A. Tumasyan,
W. Adam,
T. Bergauer,
M. Dragicevic,
J. Erö,
C. Fabjan, [......],
J. Leonard,
R. Loveless,
A. Mohapatra,
I. Ojalvo,
D. Reeder,
I. Ross,
A. Savin,
W. H. Smith,
J. Swanson,
M. Weinberg
[show abstract]
[hide abstract]
ABSTRACT: A measurement of inclusive W and Z production cross sections in pp collisions at Ös = 7 \sqrt {s} = 7 TeV is presented. The electron and muon decay channels are analyzed in a data sample collected with the CMS detector at the
LHC and corresponding to an integrated luminosity of 36 pb−1. The measured inclusive cross sections are σ(pp → WX) ×
B( \textW ® ln ) \mathcal{B}\left( {{\text{W}} \to \ell \nu } \right) = 10.31 ± 0.02 (stat.) ± 0.09 (syst.) ± 0.10 (th.) ± 0.41 (lumi.) nb and σ(pp → ZX) ×
B( \textZ ® l+ l- ) \mathcal{B}\left( {{\text{Z}} \to {\ell^{+} }{\ell^{-} }} \right) = 0.974 ± 0.007 (stat.) ± 0.007 (syst.) ± 0.018 (th.) ± 0.039 (lumi.) nb, limited to the dilepton invariant mass range 60 to 120GeV. The luminosity-independent cross section ratios
are (σ(pp → WX) ×
B( \textW ® ln ) \mathcal{B}\left( {{\text{W}} \to \ell \nu } \right) /(σ(pp → ZX) ×
B( \textZ ® l+ l- ) \mathcal{B}\left( {{\text{Z}} \to {\ell^{+} }{\ell^{-} }} \right) = 10.54 ± 0.07 (stat.) ± 0.08 (syst.) ± 0.16 (th.) and (σ(pp → W+
X) ×
B( \textW + ® l+ n ) \mathcal{B}\left( {{{\text{W}}^{ + }} \to {\ell^{+} }\nu } \right) /(σ(pp → W−
X) ×
B( \textW- ® l- [`(n)] ) \mathcal{B}\left( {{{\text{W}}^{-} } \to {\ell^{-} }\bar{\nu }} \right) = 1.421 ± 0.006 (stat.) ± 0.014 (syst.) ± 0.029 (th.). The measured values agree with next-to-next-to-leading order QCD cross
section calculations based on recent parton distribution functions.
KeywordsHadron-Hadron Scattering
Journal of High Energy Physics 04/2012; 2011(10):1-76. · 5.83 Impact Factor
